[MODERATED] [PATCH v4 6/8] [PATCH v4 6/8] Linux Patch #6

[MODERATED] [PATCH v4 6/8] [PATCH v4 6/8] Linux Patch #6

[konrad.wilk]

We can now load a different number of MSRs depending on if we are
doing VMEXIT vs VMENTER.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 arch/x86/kvm/vmx.c | 29 +++++++++++++++++++----------
 1 file changed, 19 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index f9d70b3e9fcd..e7c69ef5b918 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2412,12 +2412,18 @@ static void clear_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr)
 	}
 	i = find_msr(&m->guest, msr);
 	if (i < 0)
-		return;
+		goto skip_guest;
 	--m->guest.nr;
-	--m->host.nr;
 	m->guest.val[i] = m->guest.val[m->guest.nr];
-	m->host.val[i] = m->host.val[m->host.nr];
 	vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, m->guest.nr);
+
+skip_guest:
+	i = find_msr(&m->host, msr);
+	if (i < 0)
+		return;
+
+	--m->host.nr;
+	m->host.val[i] = m->host.val[m->host.nr];
 	vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, m->host.nr);
 }
 
@@ -2435,7 +2441,7 @@ static void add_atomic_switch_msr_special(struct vcpu_vmx *vmx,
 static void add_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr,
 				  u64 guest_val, u64 host_val)
 {
-	int i;
+	int i, j;
 	struct msr_autoload *m = &vmx->msr_autoload;
 
 	switch (msr) {
@@ -2471,21 +2477,24 @@ static void add_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr,
 	}
 
 	i = find_msr(&m->guest, msr);
-	if (i == NR_AUTOLOAD_MSRS) {
+	j = find_msr(&m->host, msr);
+	if (i == NR_AUTOLOAD_MSRS || j == NR_AUTOLOAD_MSRS) {
 		printk_once(KERN_WARNING "Not enough msr switch entries. "
 				"Can't add msr %x\n", msr);
 		return;
-	} else if (i < 0) {
+	}
+	if (i < 0) {
 		i = m->guest.nr++;
-		++m->host.nr;
 		vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, m->guest.nr);
+	}
+	if (j < 0) {
+		j = m->host.nr++;
 		vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, m->host.nr);
 	}
-
 	m->guest.val[i].index = msr;
 	m->guest.val[i].value = guest_val;
-	m->host.val[i].index = msr;
-	m->host.val[i].value = host_val;
+	m->host.val[j].index = msr;
+	m->host.val[j].value = host_val;
 }
 
 static bool update_transition_efer(struct vcpu_vmx *vmx, int efer_offset)
-- 
2.14.3

[MODERATED] Re: [PATCH v4 6/8] [PATCH v4 6/8] Linux Patch #6

[Borislav Petkov]

On Sat, Jun 23, 2018 at 09:54:20AM -0400, speck for konrad.wilk_at_oracle.com wrote:
> x86/KVM/VMX: Seperate the VMX AUTOLOAD guest/host number accounting.

WARNING: 'Seperate' may be misspelled - perhaps 'Separate'?

> 
> We can now load a different number of MSRs depending on if we are
> doing VMEXIT vs VMENTER.
> 
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> ---
>  arch/x86/kvm/vmx.c | 29 +++++++++++++++++++----------
>  1 file changed, 19 insertions(+), 10 deletions(-)

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--